1. Field of the Invention
The present invention relates to a composition comprising 1,3,5-trioxane, and more particularly to a stability-improved trioxane composition.
2. Description of the Related Art
Generally, 1,3,5-trioxane (hereinafter called "trioxane") is used for a resin intermediate and for an effective component of an insect-proofing agent.
Trioxane is a substance which is normally stable at room temperature. However, when heated and kept in a melted state for a long time in air, this substance is decomposed and oxidized in part to produce formaldehyde and formic acid and, at the same time, is polymerized in part to produce unsoluble polyoxymethylene.
Further, even in room temperature, when a solid substance having activity, such as an active silica, is in direct contact with trioxane in a solid or liquid state, or when the substance is disposed adjacent to trioxane in a solid or liquid state to contact trioxane vapor, trioxane is decomposed at the active site of the solid substance to produce formaldehyde and formic acid.
Meanwhile, thanks to advanced technology of modern industry, high-purity trioxane can be obtained, but occasionally happens to contain a small amount of formaldehyde as impurities.
Formaldehyde is a gas having an irritating odor; when the concentration of formaldehyde in trioxane is over 16 ppm by weight, the odor of formaldehyde can be felt by men. In the case trioxane is used for an insect-proofing agent, for example, comfortable use or handling cannot be achieved because of the odor. Consequently, when trioxane is used as an insect-proofing agent, the preferred concentration of formaldehyde in trioxane is less than 16 ppm by weight, especially not more than 8 ppm-by weight.
Further, since formic acid promotes the decomposition of trioxane, it is necessary to prevent the production of formic acid.
However, heretofore, there has been proposed no effective idea to prevent trioxane from being decomposed and polymerized due to heat and also to prevent trioxane from being decomposed due to an active solid substance and additionally to reduce the concentration of formaldehyde to be contained at the stage of production. Thus there is known no way of satisfying those requirements at the same time and of increasing the stability.